Effects Of Superfine Grinding Of Bran On The Rheological Properties Of Dough And Qualities Of Steamed Bread

To study the influence of superfine-ground wheat bran on the rheological properties ofdough and qualities of steamed bread,wheat brans?coarse,medium and superfine-ground?were added to low and medium protein white flours and two kinds of?southern and northern?were made.The main results are as follows:?1?The results in Mixolab showed that for two kinds of flour,compared with coarse and medium bran,the development time of dough adding superfine-ground bran was shortened,while water absorption,peak viscosity,starch hot-gel stability and starch crystallinity of dough were significantly increased?P<0.05?.?2?The maximum fermentation height Hm of the dough in the F4 was significantly reduced by adding bran with any sizes.For the same flour,compared with coarse or medium bran,Hm,the total volume of CO₂ produced and retained in the dough with superfine-ground bran were decreased significantly?P<0.05?.?3?The dynamic rheological properties of the dough showed that compared with the dough without bran,with the increase of the scanning frequency,the G'and G''values of the dough with the addition of wheat bran increased.And the G'and G''values were also increased as the bran particle sizes decreased.For the low-protein flour,compared with the dough without bran,the starch gelatinization temperature was not significantly changed after adding any sizes bran,however it was increased in the medium-protein flour.For the same flour,the starch gelatinization temperature did not change with the decrease of bran particle size.?4?With the decrease of the bran particle sizes,the T₂ relaxation time and the free water content of the dough were decreased.For the two flours,the addition of bran resulted in the gluten network structure of dough with more and larger pore than that of the dough without bran.Compared with adding coarse or medium bran,the continuity of gluten network structure of dough with the superfine-ground bran has been improved.?5?With the addition of bran,the specific volume and the EGI value of steamed bread were significantly reduced compared to bread without bran.The hardness and the relative crystallinity of the steamed bread made by superfien-ground bran were higher than those of the coarse or medium after 24 h of storage.